1 / 26

Remote Sensing:

Remote Sensing:. Observing a BIG COUNTRY. David Griffin & Edward King. CSIRO Marine and Atmospheric Research . It’s a big country, with a lot happening. Forecasting currents is like weather forecasting.

conner
Download Presentation

Remote Sensing:

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Remote Sensing: Observing a BIG COUNTRY David Griffin & Edward King CSIRO Marine and Atmospheric Research

  2. It’s a big country, with a lot happening David Griffin

  3. David Griffin

  4. David Griffin

  5. Forecasting currents is like weather forecasting People talk about using models to interpolate observations (time and space) and/or extrapolate to other variables That’s true but remember: 1) models only represent a subset (length- and time-scales) of reality -> some details cannot be forecast 2) eddy-resolving models generate eddies spontaneously, i.e., creates spectrum - > a critical number of obs are required before skillful forecasts (and accurate hindcasts) can be made What can satellites provide? David Griffin

  6. Satellites are the principal means of making models track reality Satellites are a cost-effective way of obtaining broad-scale observations of a few key variables, continuously. Especially cost effective for Australia. Remember that. Sea level (-> geostrophic velocity), wave height, sea surface temperature, salinity, gravity (->mass), colour (-> chl-a, bathymetry, etc) But there’s a catch. The ‘oceanography’ needs to be carefully teased from the raw data. Eg: ‘coastal altimetry’. Hence the formation of space agency mission-specific science teams. We are invited to respond to the ESA Sentinel-3 AO (Nov) We are already members of various STs. Typically in ‘spare time’. David Griffin

  7. Altimeters measure lines of sea level anomaly David Griffin

  8. David Griffin

  9. David Griffin

  10. Sea level anomaly: OI using 3 altimeters David Griffin

  11. David Griffin

  12. David Griffin

  13. David Griffin

  14. David Griffin

  15. Why measure sea level? Because you can. Because SLA(x,y) = f(T(x,y,z), S(x,y,z)) But there’s a catch: the Earth is lumpy (>100m). GRACE and GOCE measure the geoid down to 100km scales. Sea level = Range – orbit - geoid – path_delays – aliases Sea level = Range – orbit – MSS + MDT – path_delays – aliases 0.20m = 1350km – 1300km – 50m + 1m – 0.2m – 0.2m Spectrum of errors: 1cm to 2m Mostly well controlled. Under-sampling is the main problem. David Griffin

  16. Altimetric sea level = steric height (+ barotropic) David Griffin

  17. We read track data from NOAA/TUDELFT RADS David Griffin

  18. David Griffin

  19. Sea Surface Temperature Crucial for correcting drift in models Meso-scale information mostly lost during assimilation issues: cloud clearing, atmospheric corrections, geo-location, diurnal variability - > good validation information (when skies are clear) Feature-track currents: a mix of good and bad IMOS processes NOAA AVHRR and MODIS SST to GHRSST standard Recently discovered: geolocation errors in CAPS Microwave radiometers: low res but all-weather Need to prepare for AVHRR replacements David Griffin

  20. David Griffin

  21. Ocean Colour SeaWiFS, MODIS, MERIS Under-exploited for a decade or more IMOS now processing MODIS (aqua) routinely, from L0 data NASA SeaDAS 6.1 -> 6.4 algorithms. Back-process pre-2011 soon David Griffin

  22. David Griffin

  23. Summary For modelling, altimetry, SST and Ocean colour are the mainstays Gravity and salinity missions are the new kids on the block Next talk: Synthetic Aperture Radar Immediate future: Australian involvement in the ESA Sentinels. AO announced in a month. Australia – ESA collaboration agreement Australia – India, Aust-China, ….. David Griffin

  24. Thank you David Griffin & Edward King +61 3 6232 5244 David.Griffin@csiro.au oceancurrent.imos.org.au CSIRO Marine and Atmospheric Research

  25. David Griffin

  26. David Griffin

More Related